The two countries also reached agreements to cooperate in railway projects and shipping that could facilitate Brazilian exports to resource-hungry China.

The Asian giant's import-export bank will loan $5 billion over three years to Brazilian mining powerhouse Vale so that the company, which ships iron ore to China, can buy or rent vessels.

The two nations signed a cooperation agreement for railway projects, with Brazil hoping China will help build tracks linking the continent-sized South American country to Peru's Pacific coast.

Xi and Rousseff, whose nations marked 40 years of diplomatic relations, also launched the Portuguese-language version of China's Baidu Internet search engine.

"Our relations, which represent a truly strategic partnership, are developing at an unprecedented speed in diverse areas of cooperation," Rousseff said.

Xi said China aims to "strengthen our strategy to create an even more prosperous future for our nations."

- Alternative to US -

Xi arrived in Brazil this week for a summit of the BRICS group of emerging powers -- Brazil, Russia, India, China and South Africa -- and South American presidents.

The visit is Xi's second to Latin America since taking office last year, when he toured Mexico, Costa Rica and Trinidad and Tobago.

This week, the BRICS agreed to launch a New Development Bank to fund infrastructure projects in developing nations and an emergency reserve, drawing praise from Latin American presidents who see them as alternatives to Western-dominated financial institutions.

"We welcome this commitment to a new international order that is just and equitable," Castro said in written remarks.

Venezuela's leftist President Nicolas Maduro hailed the "relations of mutual respect between a world giant like China and Latin America."

With the visit, Xi is presenting China as an alternative to the United States in the region, analysts say.

"China is an option that matches with the leftist political sympathy that it has with some countries in the region," said Rubens Figueiredo, foreign relations professor at Sao Paulo University.

China's massive purchases of commodities and exports of manufactured goods to the region have boosted its two-way trade with Latin America to a total of $261.6 billion last year, according to official figures.

After Brazil, Xi will head to Argentina, a key source of soybeans for China, before visiting oil-supplier Venezuela and communist ally Cuba.

Despite China's growing investments in the region, it will be hard for Beijing to dislodge the United States in Latin America, said Yun Sun, East Asia expert at the Washington-based Stimson Center think-tank.

"US-Latin America long-standing, traditional ties will not be easily affected by the Chinese political and economic engagements, which are more recent and less comprehensive than US-Latin American relations," she told AFP.